Sealing arrangement for closed centrifugal separators



July 29, 1952 G. J. STREZYNSKI 2,605,045

SEALING ARRANGEMENT FOR CLOSED CENTRIFUGAL SEPARATORS Filed June 20,1951 INVENTOR. Geo/ye f Lizf ezy/rski wad/7% 0% Patented July 29, 1 952SEALING ARRANGEMENT FOR CLOSED CENTRIFUGAL SEPARATORS George J.Strezynski, Poughkeepsie, N. Y., as-

signor to The De Laval Separator Company,- New York, N. Y., acorporation of New Jersey Application June 20, 1951, Serial No. 232,517

14 Claims.

sages of the rotating separator bowl are coupled to relativelystationary feed or discharge pipes, respectively.

The prior art has offered numerous sealing arrangements for the inletand discharge paths of closed centrifugal separators. Most of thesearrangements are aimed at making the couplings from the stationarypipes, where they contact the rotating bowl, movable or flexible so asto partake of the lateral deviations and angular or tilting movements ofthe centrifugal bowl incident to its rotation. In some instances, thecouplings include sealing collars or sleeves of rubber-like materialsecured to the stationary structure or pipes and closely surroundingcentral feed and discharge tubes of the rotating bowl. However, theserubber-like seals require rather frequent replacement due to wear and,moreover, are unsuitable when a component of the feed has a chemicalaction upon the rubber-like material and thus tends to destroy it. Ithas also been proposed to use concentric metal sealingrings engaging thebowl around central discharge passages and movable on bellows formingthe flow connections to the stationary discharge pipes. Thisarrangement, however, is quite cumbersome. Furthermore, in both therubber sleeve and the bellows arrangements, the sealing pressure againstthe bowl can be adjusted, if at all, only with considerable difiiculty.

The present invention has for its principal object the provision of anarrangement for sealing the inlet or discharge paths of closedcentrifugal separators, which overcomes the above-mentioned difficultieswith prior arrangements for this purpose.

The new sealing arrangement comprises a nonrotating sealing head havinga member which terminates in an annular sealing surface complementary toand engaging a sealing surface of the separator bowl, a pivotalsupporting member for the head preferably disposed centrally of thesealing surfaces and on the bowl axis, to permit the sealing head tofollow the tilting'movements of the bowl in its rotation, and anadjustable connection between the pivotal support and the stationarystructure of the centrifuge, for adjusting the pivotal support in adirection parallel to the bowl axis to regulate the pressure between thesealing surfaces. The annular inter-engaging sealing surfaces surroundand seal a space through which a passage in the sealing headcommunicates with 'arpassage in the bowl, to provide a feed or dischargepath between the bowl and a stationary pipe connected to the head. I :i

For a better understanding of the invention, reference may be had to theaccompanying drawing in which the single figure is a vertical sectionalview of a centrifugal separator showing the upper part of the separatorbowl, thesealing head and the pivotal support mounted in operatingposition in accordance with the invention.

Referring to the drawing, the separator bowl, shown generally at I, issupported on a stationary structure for rotation about an axis. Theparticular mounting for the bowl and the details of the separatingchamber in the bowl and the feed passage thereto; are not shown on thedrawing, as they may be conventional. Theseparator bowl has a neck 5surrounding the neck 6 of a top disc in the bowl, the annular members 5and 6 being arranged concentrically with the bowl axis so as to defineinner and outer discharge passages and 8, respectively, for dischargingtwo separated, comp nents from the separating chamber. At the top of thebowl, the extremities of members 5 and 6 terminate in a common plane soas to form annular concentric surfaces 9 normal to the bowl axis.

The sealing head 2, which is non-rotating, comprises a casting ID of anysuitable material and having outwardly extending discharge passages orconduits I I and I2. As will be evident from ,the drawing, passages IIand I2 communicate with inner passage I and outer passage 8 of the bowl,respectively, whereby the separated materials from the bowl are conveyedseparately through the head. Flexible piping I3 and I4 may be secured tothe head around the discharge passages II and .I2, respectively-so as toconvey the separated materials to the desired locations. The head hascircular depending bottom members terminating in annular concentricsealing surfaces I5 surrounding the entrance ends of the passages I Iand I2, respectively. The surfaces I5 are complementary to andengagecorresponding sealing surfaces of thebowl I.

.In the embodiment'shown in the drawing, the sealing surfaces of thebowl are formed by annular discs I6, I! secured to the respectiveannular surfaces 9 at the top of the bowl. These discs are in slidingengagement with the sealing surfaces I5, respectively, of the head toprovide a substantially liquid-tightl coupling of the passages l-I I and8-I2. The material chosen for these discs will, of course. depend uponthe mixture to be separated by the centrifuge. For example, whenchloroform is one of the constituents to be separated, it is advisableto use Teflon discs, since rubber, the usual sealing medium, is attackedchemically by chloroform. Alternatively, a bi-metallic arrangement couldbe used wherein -stellite or a similar material is bonded to one pair ofthe surfaces 9 and I5 and another suitable metal is plated or secured tothe other pair.

In order to maintain a sealing pressure between the surfaces |5-|6 and|5||, and support the sealing head laterally, a pivotal support 3 isprovided for the sealing head 2. The pivotal support 3 engages in acentral depression or recess l8 formed in the head and located on therotation axis of the bowl. The pivotal support includes a cylindricaladjusting device l9 threaded at for insertion in the stationarystructure, part of which is indicated at 4, the device l9 having areduced stem portion 20. A hollow cup-or supporting member 2| has at thetop a central opening loosely receiving the stem 26 and surrounded by ashoulder 22. The'lower portion of the cup tapers downward and fits intoa downwardly tapered part of the recess Hi, the reduced end of the cupengaging the head at the bottom of the recess. However, the recess has asharper taper than the cup, to provide a clearance around-the cup aboveits reduced end, as shown at 23. A biasing element is interposed betweenshoulder's 22-28 of the cup 2| and device l9, respectively, and is shownin the form of a compression spring coiled around the stem 20. Thethreaded part 20' and the spring 25 form an adjustable yieldingconnection between the pivotal supporting member 2| and the stationarystructure 4, for regulating the pressure between the sealing surfacesl5-|6 and-lS-H.

A hand wheel 21, integral with adjusting device I9, is provided forimparting rotary motion thereto. As will be apparent from the drawing,the rotation of the device it increases or decreases the force appliedby the biasing spring 25 and thus determines the pressure with which thecup or pivotal supporting member 2| will bear on the head 2 indepression l8. This arrangement' has the advantage that the actualpressure at the sealing surfaces |5|8 and l5-l1 may be'manually adjustedwhile the centrifuge is in operation, so that there is no need to stopthe centrifuge for this purpose.

With the new construction, substantially no leakage will take place atthe sealing surfaces |5-||i and'|5l'|. In order to prevent re-mixture ofseparated components due to any such leakage, and to recover theleakage, annular grooves 29 are formed in the sealing surfaces |5 of thehead,'these grooves surrounding the entrance ends of the passages H andi2, respectively. The grooves 29 are interconnected by branch ducts 30of an outlet duct 3|l in the sealing head 2. A fitting or nipple 3|secured to the body l0 serves to connect the duct 30* to a source ofvacuum (not shown). In this way, any leakage between the sealingsurfaces |5 -|6 and |5-|'| may be collected and returned to thecentrifugal bowl in the feed stream.

The sealing head 2 may also be supported laterally by a cushioning mount32 in the form of a rubber-like ring closely surrounding the circulardepending portion of the head and interposed betweenthe latterand a part33 of the stationary frame of the centrifuge. The cushion 4 32 permitssome lateral movement of the head 2 and also tilting thereof with thebowl.

It will be understood from the drawing that the entrance or lower end ofpassage I2 in the sealing head is annular and overlies the outer annularpassage 8 of the bowl, as shown at l2. This annular passage portion |2surrounds the centrally located entrance end of the other passage in thehead and merges around the latter passage and recess IS, with the mainportion of the passage l2, as indicated by the dotted line l2". Theentrance or lower end of passage overlies the central passage I of thebowl and merges with the main portion of passage through a lateralthroat Il In the operation of the centrifuge, the rotat mg rings l6 andll of the bowl can slide on the respective sealing surfaces iii of thehead 2, to

accommodate lateral displacements of the bowl incident to its rotation.The sealing head itself can also undergo limited lateral movementagainst the cushion 32, by reason of the loose fit between the centeringcup or pivotal support 2| and the fixed stem 29. The cushion 32 and thecup 2| allow the sealing head to tilt so as to follow the angularmovements of the bowl during its rotation, while maintaining a tightengagement of the sealing surfaces l5|8 and |5|'|. This tilting of thehead occurs about the lower portion of the stem 23 as a fulcrum and isyieldingly opposed by the spring 25, which tends to resist tilting ofthe cup relative to stem 20. The clearance 23 also allows some tiltingof the head relative to the cup, in addition to facilitating a firmwedging action of the cup in the recess l8. The cup 2| could, of course,be made integral with the stem 28, in which case the head tilting woulddepend upon the clearance 23, but in either case the cup will act as apivotal supporting member for the head. The sealing head 2 may bereadily removed from the centrifuge, for cleaning, etc., by simplyunscrewing the member l9 from the frame part i and disconnectingtheflexible pipes |3|4 from the head.

While the invention has been specifically described and illustrated inconnection with the outlet of the centrifuge, it will be understood thatthe arrangement can also be applied to the inlet of the centrifuge withequal facility and with the same advantages.

I claim:

1. In a centrifuge having a stationary structure and a centrifugal bowlsupported by said structure for rotation about an axis, the bowl havingan annular sealing surface concentric with the axis and forming apassage communieating with the interior of the bowl, the combination ofa sealing head having a member termimating in an annular surface insealing engagement with said first surface and at least partly defininga passage in the head communicating with the bowl passage, a pivotalsupporting member engaging the head and on which the head is tiltablerelative to the stationary structure and an adjustable connectionbetween the pivotal supporting member and said structure for regulatingthe sealing pressure between said surfaces.

2. A combination according to claim 1, in which said adjustableconnection includes a yielding biasing element urging the pivotalsupporting member against the head.

3 A combination according to claim 1, in which the pivotal supportingmember is located centrally of said surfaces and on the bowl axis.

4. A combination according to claim 1, comprising also a yieldinglateral support for the head at least partly surrounding the head andinterposed between the head and the stationary structure.

5. A combination according to claim 1, in which the head has a recessdisposed on the bowl axis and receiving the pivotal supporting member.

6. A combination according to claim 1, in which the head has a taperedrecess, the pivotal supporting member being tapered and fitting into thetapered recess.

'7. A combination according to claim 1, in which the head has a taperedrecess, the pivotal supporting member bein tapered and fitting into thetapered recess with a clearance around the enlarged portion of thetapered supporting member.

8, A combination according to claim 1, in which said connection includesan adjustment device on the stationary structure, the pivotal supportingmember being itself pivotable on said device.

9. A combination according to claim 1, in which said connection includesan adjustment device on the stationary structure, the pivotal supportingmember being itself pivotable on said device, and a yielding biasingelement between the adjustment device and said supporting member forurging the pivotal supporting member against the head and opposingpivoting movement of said supporting member relative to the adjustmentdevice.

10. In a centrifuge having a stationary structure and a centrifugal bowlsupported by said structure for rotation about an axis, the bowl havingan annular sealing surface concentric with the axis and forming apassage communicating with the interior of the bowl, the combination ofa sealing head having a member terminating in an annular surface insealing engagement with said first surface and at least partly defininga passage in the head communicating with the bowl passage, a pivotalsupporting member engaging the head and on which the head is tiltablerelative to the stationary structure, and a yielding connection betweenthe pivotal supporting member and said structure, including a biasingelement acting on the supporting member'to urge said surfaces together.

11. In a centrifuge having a stationary structure and a centrifugal bowlsupported by said structure for rotation about an axis, the bowl havingan annular sealing surface concentric with the axis and forming apassage communicating with the interior of the bowl, the combination ofa sealing head having a member terminating in an annular surface insealing engagement with said first surface and at least partly defininga passage in the head communicating with the bowl passage, and a pivotalsupporting member connected to the stationary structure and engaging thehead centrally of saidsurfaces and on the bowl axis, the head beingtiltable on said supporting member relative to the stationary structure.

12. In a centrifuge having a stationary structure and a centrifugal bowlsupported thereon for rotation about an axis, the bowl having annularsealing surfaces concentric with the axis and forming a central passageand also an outer annular passage communicating with the bowl interior,the combination of a sealing head having members terminating in annularconcentric surfaces in sealing engagement with said bowl surfaces,respectively, and at least partly defining a central passage and anouter passage communicating, respectively, with said central passage andsaid outer passage of the bowl, said outer passage of the headsurrounding said central passage of the head and merging into a mainlateral passage in the head, said last central passage leading laterallyaway from said main lateral passage, a pivotal supporting memberengaging the head above said central passage therein and on which thehead is tiltable relative to the stationary structure, and a biasingconnection between the supporting member and the stationary structurefor urging the head against said bowl surfaces.

13. A combination according to claim 12, in which the head has anannular groove in each of said concentric sealing surfaces of the head,the head also having a vacuum passage communicating with said grooves.

14. A combination according to claim 12, in which the head has a centralrecess overlying the central passage therein and partly surrounded bysaid outer passage of the head, the pivotal supporting member engagingthe head in said recess.

GEORGE J. STREZYNSKI.

REFERENCE S CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number

